Over the past few years, there have been many complaints about video game endings -- that they're rushed, that they're unsatisfying, that it feels like the developers spent more time on other parts of the game (usually true). But no unfinished ending holds a candle to Saga Frontier.
Saga Frontier, a quirky role-playing game that Square released in 1998 for the PlayStation 1, has an ambitious structure centering on seven protagonists, each with his or her own campaign. One campaign revolves around a teenage boy who becomes a superhero; another is about a robot who has to recover its memory, and so on.
One of Saga Frontier's best stories stars a wizard named Blue who has just graduated from a far less pleasant version of Hogwarts. He is told to go out and gather magic from across the galaxy, then to come back and fight his twin brother, Rouge, for wizard supremacy. At the end of the duel, the two brothers merge, revealing that they were actually two sides of the same person all along. (If you lose, you'll play as Rouge for the rest of the game.) Then, the wizards ask Blue/Rouge to descend into a twisted version of Hell and prevent demons from coming out and invading the earth.
And then, well, this happens (skip to 8:40):
Makes all those complaints about Mass Effect 3 seem pretty quaint, don't you think? At least that game's ending actually -- you know -- existed..
Although Blue's ending came as a shock to western Saga Frontier players back in the 1990s, it got an explanation in The Essense of SaGa Frontier, a Japanese tome that revealed a great deal about the game (including a whole lot of cut content). As Saga Frontier player RedBoot explained in a Let's Play of the game:
It turns out that long ago the Magic Kingdom sealed away the demons, but knew the seal would someday break. Thus the plan to make a wizard who could control all spells was conceived. Blue/Rouge was that plan, and it was a success. However, could Rouge could actually beat Hell's Lord? Apparently the remaining wizards of the Magic Kingdom weren't interested in taking any chances. When Hell's Lord was busy fighting Rouge, the wizards sealed away Hell, freezing it in time. Hence the sudden end to the battle. Essence goes on to state that Rouge eventually breaks free of the seal, led by the cries of his friends.
How metaphorical. The other answer is likely that Saga Frontier's developers didn't have time to finish the ending to Blue's campaign, so they just stuck "The End" in the middle of a boss fight and called it a day. Remember that the next time you're disappointed by the finale of a video game.